Morphology and mineralogy and magnetic parameters were analysed in
atmospheric dust samples collected in 7 cities of Upper Silesia region (South
Poland). The study was carried on by means of EDS spectroscopy, SEM
technique, X-ray diffraction and Mössbauer spectroscopy. Special attention was
paid to the magnetic fraction of studied dusts that is a potential carrier trace
elements emitted to the environment. To assess the total content of magnetic
fraction in bulk dust samples, mass specific magnetic susceptibility (χ) was
measured using a MS2B \“Bartington” sensor, then a physical separation of
magnetic particles (mostly of technogenic origin) was conducted. The dusts
revealed high diversity of χ value, which depended both on the sampling site and
the prevailing direction of winds during the period of dust deposition on filters.
In the case of atmospheric dusts, the χ value ranged from 10 × 10-8m3kg-1 to 1577
× 10-8m3kg-1. The highest values were detected in samples collected within the
range of metallurgical dust emission. The morphological and mineralogical
analyses showed that among the technogenic magnetic fraction ferrimagnetic
spherules built of iron oxides from magnetite-maghemite series with admixtures
of wustite, hematite, goethite and non-stoichiometric Fe-Zn oxides were the
predominant structures. Significant differences in magnetic mineralogy of dusts
coming from different branches of industry were observed. Magnetic fraction
produced by the metallurgy and coke industry were mostly in forms of tightly
compacted aggregates with well-formed crystal structure whereas in fly ashes
from coal combustion spherical forms (typical ferromagnetic spherules) were
mostly observed. Here the predominant magnetic minerals are: magnetite,